Influence of branched chains on the mesomorphic properties of symmetrical and unsymmetrical triphenylene discotic liquid crystals

A series of novel symmetrical and unsymmetrical triphenylene-based discotic liquid crystalline materials with one or six branched peripheral alkoxy chains have been prepared. These materials have been compared with analogous known symmetrical and unsymmetrical compounds to reveal a balance between steric and space-filling effects of the peripheral branched chains, which significantly affects intermolecular forces of attraction and packing, and hence affects melting and isotropisation temperatures of the liquid crystalline materials. The desired result of reduction of melting points and enhancement of isotropisation temperatures has been accomplished by use of branched alkoxy chains in both symmetrical and unsymmetrical materials.